plan9-gpl/sys/man/1/chmod

.TH CHMOD 1 
.SH NAME
chmod \- change mode
.SH SYNOPSIS
.B chmod
.I mode file ...
.SH DESCRIPTION
The mode of
each named file
is changed
according to
.IR mode,
which may be an octal number or a symbolic change to the existing mode.
A
.I mode
is an octal
number constructed
from the OR of the
following modes.
.TF 0000
.TP
0400
read by owner
.TP
0200
write by owner
.TP
0100
execute (search in directory) by owner
.TP
0070
read, write, execute (search) by group
.TP
0007
read, write, execute (search) by others
.PD
.PP
A symbolic
.I mode
has the form:
.IP
.RI [who]
.I op permission
.PP
The
.I who
part is a combination
of the letters 
.B u
(for user's permissions),
.B g
(group)
and
.B o
(other).
The letter
.B a
stands for
.BR ugo .
If
.I who
is omitted,
the default is
.BR a .
.PP
.I Op
can be
.B +
to add
.I permission
to the file's mode,
.B -
to take away
.IR permission ,
and
.B =
to assign
.I permission
absolutely
(all other bits will
be reset).
.PP
.I Permission
is any combination of the letters
.B r
(read),
.B w
(write),
.B x
(execute),
.B a
(append only),
.B l
(exclusive access),
and
.B t
(temporary file).
.PP
Only the owner of a file or the group leader of its group
may change the file's mode.
.SH SOURCE
.B /sys/src/cmd/chmod.c
.SH "SEE ALSO"
.IR ls (1),
.IR stat (2),
.IR stat (5)